# United States **De p** **artment of** **the Interior** 

**OFFICE OF**  **THE SECRETARY**  **Washingron, DC**  **20240**



# ocr **2 1 zoo�**  **Mr. Bhara** **t Mathur**  **Acting Regio�al**  **Administrator U.S.**  **Environmental Protection**  **Agency, Region**  **5 77**  **West Jackson**  **Boulevard Chicago,**  **Illinois 60604-3507** 

**Dear Mr.**  **Mathur:** 

# Exhibit**A**

**On Septe** **mber 3,**  **2009, the**  **National Parks**  **Conservation Asso** **ciation (NPCA),**  **Minnesota Center**  **for Environmental**  **Advocacy, Friends**  **of the**  **Boundary Waters**  **Wilderness, and**  **Voyageurs National**  **Park Association**  **petitioned the**  **Department of** **the Interior**  **(DOI) to**  **certify to**  **the Minnesota**  **Pollution Control**  **Agency (MPCA)**  **that a**  **portion of** **the visibility**  **impairmen t**  **in Voyageurs**  **and Isle**  **Royale National**  **Parks is**  **reasonably attributable**  **to pollution**  **emissions from**  **Xcel Ener** **gy 's**  **Sherburne County** **Generating Pla** **nt (Sherco)**  **in central**  **Minnesota. 1**  **have enclosed**  **a copy**  **of this** **petition for**  **your review. Under**  **40 C.F.R.**  **§ 51.302(c)(l),**  **"[t]he affected**  **Federal Land**  **Manager may**  **certify to**  **the State,**  **at any**  **time, that**  **there exists**  **reasonably attributable**  **impairment of** **visibility in**  **any mandatory**  **Class I**  **Federal area."**  **In this**  **cas e,**  **because the**  **Environmental Protection**  **Agency (EPA)** **currently administers**  **the 1980**  **Visibility Protection**  **Rules for**  **the State**  **of Minnesota**  **through a**  **Federal Implementation**  **Plan, any**  **such visibility**  **impairment certification**  **should be**  **directed to**  **the EPA,**  **not the**  **MPCA. For**  **the reasons**  **discussed below,**  **I am**  **granting the**  **NPCA's request,**  **and hereby**  **certify that**  **there exists**  **reasonably attributable impairment**  **of visibility**  **at Voyageurs**  **and Isle**  **Royale due**  **to emissions**  **from the**  **Sherco facility.** 

**Background On**  **November 30,**  **1979, the**  **DOl identified**  **Voyageurs and**  **Isle Royale**  **as Class**  **I areas**  **where visibility**  **is an**  **important value.**  **On November**  **14, 1985,**  **the DOl**  **certified to**  **the EPA**  **that visibility**  **impairment existed**  **in Voyageurs**  **and Isle**  **Royale, and**  **all other**  **Class I**  **areas in**  **its jurisdiction**  **in the**  **lower 48**  **States.**

**Sherco consists**  **of three**  **coal- fired**  **units with**  **a total**  **plant electrical**  **output rating**  **of 2,25** **5 megawatts.**  **The plant**  **is located**  **in Becker,**  **Minnesota, and**  **based on**  **Xcel Energy's**  **analyses, its**  **emissions impact visibility**  **at Voyageurs**  **and Isle**  **Royale, both**  **mandatory Class**  **I Federal**  **areas administered**  **by the**  **National Park**  **Service (NPS).**  **According to**  **EPA's Clean**  **Air Markets**  **Database, in**  **2008, out**  **of 1,228**  **power plants**  **in the**  **United States,**  **Sherco ranked**  **number 101**  **in sulfur**  **diox ide**  **emissions at**  **23,419 tons**  **and number**  **33 for**  **nitrogen oxides (NOx)**  **emissions at**  **17,713 tons.**  **Only Sherco**  **Units 1**  **and 2**  **are suhject**  **to the**  **Best Available**  **Retrofit Technology**  **(BART) provisions**  **of the**  **Regional Haze**  **Rule. Xcel**  **Energy initially**  **proposed to**  **install Selective**  **Catalytic Reduction**  **(SCR) at**  **Sherco Units 1**  **and 2**  **to control**  **NOx emissions from**  **those units.**  **However, for**  **reasons unclear**  **to us,**  **Xcel Energy later withdrew**  **its SC** **R proposal**  **in favor**  **of the**  **existing combustion**  **controls for Sherco**  **Units 1**  **and 2.**  **On June**  **26,2009, and**  **then**

# Exhibit**1\**

**again on**  **September 3,**  **2009, the** **NPS submitted**  **extensive comments**  **in support**  **of its**  **position that**  **SCR is**  **indeed BART**  **for Sherco**  **Units 1**  **and 2**  **(copy enclosed).**  **Despite our**  **comments, and**  **the fact**  **that the**  **MPCA determined**  **that SCR**  **was BART**  **for the**  **smaller Minnesota**  **Power Boswell**  **Unit 3**  **and Xcel**  **Energy King**  **Units I**  **and 2,**  **the MPCA**  **agreed with**  **Xcel Energy** **that the**  **existing combustion controls** **were BART**  **for Sherco**  **Units I**  **and 2.** 



### Sherco's**Air Quality Impacts** **at Voyageurs**  **and Isle**  **Royale According**  **to the**  **EPA's BART**  **guidelines, a**  **single source**  **that is**  **responsib�e for**  **a 0.5**  **deciview (dv)**  **or more**  **change in**  **visibility should**  **be considered**  **to "contribute**  **to" visibility impairment.**  **Xcel Energy's**  **regional haze**  **modeling su** **bmitted to**  **the MPCA**  **in October**  **2006, showed**  **that, for**  **the 2002-2004**  **modeling period,**  **combined impacts**  **from Sherco**  **Units I**  **and 2**  **were above**  **the EPA**  **0.5 dv** **threshold on**  **165 days**  **at Voyageur**  **s and**  **I 59** **days at**  **Isle Royale,**  **with maximum**  **impacts of** **2.34 dv**  **and 1.79**  **dv respectively.** 



### Conclusion **Based on**  **Xcel Energy's**  **modeling results,**  **a portion**  **of the**  **existing visibility**  **impairment in**  **Voyageurs and**  **Isle Royale**  **is reasonably**  **attributable to** **pollution emissions**  **from Sherco Units**  **1 and**  **2. As**  **noted in**  **our previous**  **comments on**  **MPCA's proposed**  **regional haze**  **rules, we**  **believe that**  **SCR at**  **0.06 pounds**  **per million**  **British thermal**  **units heat**  **input (30-day**  **rolling average)**  **is BART**  **for the**  **Sherco facility.**  **Applyin g**  **SCR would** **reduce NOx**  **emissions from** **the facility**  **by 80**  **percent, or** **more than l** **0,000 tons**  **per year.** 

**We would**  **be happy**  **to discuss**  **our concerns**  **directly with**  **you and**  **the MPCA.**  **Please direct**  **any questions**  **you have**  **regarding this**  **matter to**  **Chris Holbeck,**  **Natural Resource**  **Program Manager,**  **Midwest Region,**  **NPS, at**  **402/66l-I864. By**  **working together,**  **I am**  **confident that**  **we can**  **reach**

**a solution**  **that will**  **preserve the**  **visibility at**  **Voyageurs and**  **Isle Royale**  **for the**  **enjoyment of future**  **generations.**

**Since rely,** 

**Thomas L.**  **Strickland Assistant**  **Secretary for**  **Fish and**  **Wildlife and**  **Parks**

**Enclosure**

**cc:**

**Secretary Tom**  **Vilsack, Department**  **of Agriculture,**  **1400 Independence**  **Avenue, S.W.,**  **Washington, District of** **Columbia 20250**  **Mr. Paul**  **Eger, Commissioner,**  **Minnesota Pollution Control**  **Agency, 520**  **Laf ayette**  **Road North,**  **St. Paul, Minnesota**  **55155-4194 Mr.**  **Ernest Quintana,**  **Regional Director,**  **Midwest Region,**  **National Park**  **Service, 601**  **Riverfront Drive,**  **Omaha, Nebraska 68102**